gdb/i386v-nat.c

   1 /* Intel 386 native support for SYSV systems (pre-SVR4).
   2    Copyright (C) 1988, 1989, 1991, 1992, 1994 Free Software Foundation, Inc.
   3
   4 This file is part of GDB.
   5
   6 This program is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2 of the License, or
   9 (at your option) any later version.
  10
  11 This program is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with this program; if not, write to the Free Software
  18 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  19
  20 #include "defs.h"
  21 #include "frame.h"
  22 #include "inferior.h"
  23 #include "language.h"
  24 #include "gdbcore.h"
  25
  26 #ifdef USG
  27 #include <sys/types.h>
  28 #endif
  29
  30 #include <sys/param.h>
  31 #include <sys/dir.h>
  32 #include <signal.h>
  33 #include <sys/user.h>
  34 #include <sys/ioctl.h>
  35 #include <fcntl.h>
  36
  37 #ifdef TARGET_HAS_HARDWARE_WATCHPOINTS
  38 #include <sys/debugreg.h>
  39 #endif
  40
  41 #include <sys/file.h>
  42 #include "gdb_stat.h"
  43
  44 #ifndef NO_SYS_REG_H
  45 #include <sys/reg.h>
  46 #endif
  47
  48 #include "floatformat.h"
  49
  50 #include "target.h"
  51
  52 \f
  53 /* this table must line up with REGISTER_NAMES in tm-i386v.h */
  54 /* symbols like 'EAX' come from <sys/reg.h> */
  55 static int regmap[] =
  56 {
  57   EAX, ECX, EDX, EBX,
  58   UESP, EBP, ESI, EDI,
  59   EIP, EFL, CS, SS,
  60   DS, ES, FS, GS,
  61 };
  62
  63 /* blockend is the value of u.u_ar0, and points to the
  64  * place where GS is stored
  65  */
  66
  67 int
  68 i386_register_u_addr (blockend, regnum)
  69      int blockend;
  70      int regnum;
  71 {
  72   struct user u;
  73   int fpstate;
  74   int ubase;
  75
  76   ubase = blockend;
  77   /* FIXME:  Should have better way to test floating point range */
  78   if (regnum >= FP0_REGNUM && regnum <= (FP0_REGNUM + 7))
  79     {
  80 #ifdef KSTKSZ   /* SCO, and others? */
  81       ubase += 4 * (SS + 1) - KSTKSZ;
  82       fpstate = ubase + ((char *)&u.u_fps.u_fpstate - (char *)&u);
  83       return (fpstate + 0x1c + 10 * (regnum - FP0_REGNUM));
  84 #else
  85       fpstate = ubase + ((char *)&u.i387.st_space - (char *)&u);
  86       return (fpstate + 10 * (regnum - FP0_REGNUM));
  87 #endif
  88     }
  89   else
  90     {
  91       return (ubase + 4 * regmap[regnum]);
  92     }
  93
  94 }
  95 \f
  96 #ifdef TARGET_HAS_HARDWARE_WATCHPOINTS
  97
  98 #if !defined (offsetof)
  99 #define offsetof(TYPE, MEMBER) ((unsigned long) &((TYPE *)0)->MEMBER)
 100 #endif
 101
 102 /* Record the value of the debug control register.  */
 103 static int debug_control_mirror;
 104
 105 /* Record which address associates with which register.  */
 106 static CORE_ADDR address_lookup[DR_LASTADDR - DR_FIRSTADDR + 1];
 107
 108 static int
 109 i386_insert_aligned_watchpoint PARAMS ((int, CORE_ADDR, CORE_ADDR, int,
 110                                            int));
 111
 112 static int
 113 i386_insert_nonaligned_watchpoint PARAMS ((int, CORE_ADDR, CORE_ADDR, int,
 114                                            int));
 115
 116 /* Insert a watchpoint.  */
 117
 118 int
 119 i386_insert_watchpoint (pid, addr, len, rw)
 120      int pid;
 121      CORE_ADDR addr;
 122      int len;
 123      int rw;
 124 {
 125   return i386_insert_aligned_watchpoint (pid, addr, addr, len, rw);
 126 }
 127
 128 static int
 129 i386_insert_aligned_watchpoint (pid, waddr, addr, len, rw)
 130      int pid;
 131      CORE_ADDR waddr;
 132      CORE_ADDR addr;
 133      int len;
 134      int rw;
 135 {
 136   int i;
 137   int read_write_bits, len_bits;
 138   int free_debug_register;
 139   int register_number;
 140
 141   /* Look for a free debug register.  */
 142   for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)
 143     {
 144       if (address_lookup[i - DR_FIRSTADDR] == 0)
 145         break;
 146     }
 147
 148   /* No more debug registers!  */
 149   if (i > DR_LASTADDR)
 150     return -1;
 151
 152   read_write_bits = ((rw & 1) ? DR_RW_READ : 0) | ((rw & 2) ? DR_RW_WRITE : 0);
 153
 154   if (len == 1)
 155     len_bits = DR_LEN_1;
 156   else if (len == 2)
 157     {
 158       if (addr % 2)
 159         return i386_insert_nonaligned_watchpoint (pid, waddr, addr, len, rw);
 160       len_bits = DR_LEN_2;
 161     }
 162
 163   else if (len == 4)
 164     {
 165       if (addr % 4)
 166         return i386_insert_nonaligned_watchpoint (pid, waddr, addr, len, rw);
 167       len_bits = DR_LEN_4;
 168     }
 169   else
 170     return i386_insert_nonaligned_watchpoint (pid, waddr, addr, len, rw);
 171
 172   free_debug_register = i;
 173   register_number = free_debug_register - DR_FIRSTADDR;
 174   debug_control_mirror |=
 175     ((read_write_bits | len_bits)
 176      << (DR_CONTROL_SHIFT + DR_CONTROL_SIZE * register_number));
 177   debug_control_mirror |=
 178     (1 << (DR_LOCAL_ENABLE_SHIFT + DR_ENABLE_SIZE * register_number));
 179   debug_control_mirror |= DR_LOCAL_SLOWDOWN;
 180   debug_control_mirror &= ~DR_CONTROL_RESERVED;
 181
 182   ptrace (6, pid, offsetof (struct user, u_debugreg[DR_CONTROL]),
 183           debug_control_mirror);
 184   ptrace (6, pid, offsetof (struct user, u_debugreg[free_debug_register]),
 185           addr);
 186
 187   /* Record where we came from.  */
 188   address_lookup[register_number] = addr;
 189   return 0;
 190 }
 191
 192 static int
 193 i386_insert_nonaligned_watchpoint (pid, waddr, addr, len, rw)
 194      int pid;
 195      CORE_ADDR waddr;
 196      CORE_ADDR addr;
 197      int len;
 198      int rw;
 199 {
 200   int align;
 201   int size;
 202   int rv;
 203
 204   static int size_try_array[16] = {
 205     1, 1, 1, 1,                 /* trying size one */
 206     2, 1, 2, 1,                 /* trying size two */
 207     2, 1, 2, 1,                 /* trying size three */
 208     4, 1, 2, 1                  /* trying size four */
 209   };
 210
 211   rv = 0;
 212   while (len > 0)
 213     {
 214       align = addr % 4;
 215       /* Four is the maximum length for 386.  */
 216       size = (len > 4) ? 3 : len - 1;
 217       size = size_try_array[size * 4 + align];
 218
 219       rv = i386_insert_aligned_watchpoint (pid, waddr, addr, size, rw);
 220       if (rv)
 221         {
 222           i386_remove_watchpoint (pid, waddr, size);
 223           return rv;
 224         }
 225       addr += size;
 226       len -= size;
 227     }
 228   return rv;
 229 }
 230
 231 /* Remove a watchpoint.  */
 232
 233 int
 234 i386_remove_watchpoint (pid, addr, len)
 235      int pid;
 236      CORE_ADDR addr;
 237      int len;
 238 {
 239   int i;
 240   int register_number;
 241
 242   for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)
 243     {
 244       register_number = i - DR_FIRSTADDR;
 245       if (address_lookup[register_number] == addr)
 246         {
 247           debug_control_mirror &=
 248             ~(1 << (DR_LOCAL_ENABLE_SHIFT + DR_ENABLE_SIZE * register_number));
 249           address_lookup[register_number] = 0;
 250         }
 251     }
 252   ptrace (6, pid, offsetof (struct user, u_debugreg[DR_CONTROL]),
 253           debug_control_mirror);
 254   ptrace (6, pid, offsetof (struct user, u_debugreg[DR_STATUS]), 0);
 255
 256   return 0;
 257 }
 258
 259 /* Check if stopped by a watchpoint.  */
 260
 261 CORE_ADDR
 262 i386_stopped_by_watchpoint (pid)
 263     int pid;
 264 {
 265   int i;
 266   int status;
 267
 268   status = ptrace (3, pid, offsetof (struct user, u_debugreg[DR_STATUS]), 0);
 269   ptrace (6, pid, offsetof (struct user, u_debugreg[DR_STATUS]), 0);
 270
 271   for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)
 272     {
 273       if (status & (1 << (i - DR_FIRSTADDR)))
 274         return address_lookup[i - DR_FIRSTADDR];
 275     }
 276
 277   return 0;
 278 }
 279
 280 #endif /* TARGET_HAS_HARDWARE_WATCHPOINTS */
 281
 282 #if 0
 283 /* using FLOAT_INFO as is would be a problem.  FLOAT_INFO is called
 284    via a command xxx and eventually calls ptrace without ever having
 285    traversed the target vector.  This would be terribly impolite
 286    behaviour for a sun4 hosted remote gdb.
 287
 288    A fix might be to move this code into the "info registers" command.
 289    rich@cygnus.com 15 Sept 92. */
 290 i386_float_info ()
 291 {
 292   struct user u; /* just for address computations */
 293   int i;
 294   /* fpstate defined in <sys/user.h> */
 295   struct fpstate *fpstatep;
 296   char buf[sizeof (struct fpstate) + 2 * sizeof (int)];
 297   unsigned int uaddr;
 298   char fpvalid = 0;
 299   unsigned int rounded_addr;
 300   unsigned int rounded_size;
 301   extern int corechan;
 302   int skip;
 303
 304   uaddr = (char *)&u.u_fpvalid - (char *)&u;
 305   if (target_has_execution)
 306     {
 307       unsigned int data;
 308       unsigned int mask;
 309
 310       rounded_addr = uaddr & -sizeof (int);
 311       data = ptrace (3, inferior_pid, (PTRACE_ARG3_TYPE) rounded_addr, 0);
 312       mask = 0xff << ((uaddr - rounded_addr) * 8);
 313
 314       fpvalid = ((data & mask) != 0);
 315     }
 316 #if 0
 317   else
 318     {
 319       if (lseek (corechan, uaddr, 0) < 0)
 320         perror ("seek on core file");
 321       if (myread (corechan, &fpvalid, 1) < 0)
 322         perror ("read on core file");
 323
 324     }
 325 #endif  /* no core support yet */
 326
 327   if (fpvalid == 0)
 328     {
 329       printf_unfiltered ("no floating point status saved\n");
 330       return;
 331     }
 332
 333   uaddr = (char *)&U_FPSTATE(u) - (char *)&u;
 334   if (target_has_execution)
 335     {
 336       int *ip;
 337
 338       rounded_addr = uaddr & -sizeof (int);
 339       rounded_size = (((uaddr + sizeof (struct fpstate)) - uaddr) +
 340                       sizeof (int) - 1) / sizeof (int);
 341       skip = uaddr - rounded_addr;
 342
 343       ip = (int *)buf;
 344       for (i = 0; i < rounded_size; i++)
 345         {
 346           *ip++ = ptrace (3, inferior_pid, (PTRACE_ARG3_TYPE) rounded_addr, 0);
 347           rounded_addr += sizeof (int);
 348         }
 349     }
 350 #if 0
 351   else
 352     {
 353       if (lseek (corechan, uaddr, 0) < 0)
 354         perror_with_name ("seek on core file");
 355       if (myread (corechan, buf, sizeof (struct fpstate)) < 0)
 356         perror_with_name ("read from core file");
 357       skip = 0;
 358     }
 359 #endif  /* 0 */
 360
 361   fpstatep = (struct fpstate *)(buf + skip);
 362   print_387_status (fpstatep->status, (struct env387 *)fpstatep->state);
 363 }
 364
 365 #endif /* never */